[mythtv-users] v30 unsmooth playback

John Pilkington johnpilk222 at gmail.com
Sun Feb 3 17:54:31 UTC 2019

On 03/02/2019 16:35, Tim Draper wrote:
>   ---- On Sat, 02 Feb 2019 04:39:29 +0000 Stephen Worthington <stephen_agent at jsw.gen.nz> wrote ----
>   > On Fri, 01 Feb 2019 20:16:46 +0000, you wrote:
>   >
>   > > ---- On Fri, 01 Feb 2019 19:44:28 +0000 Jon Boehm <jon.s.boehm at gmail.com> wrote ----
>   > > > I saw this with fixes/29 backend and pre-30 Nvidia Shield Android frontend.  Its annoying but has not happened so often to be a super large problem.  Like a couple of studded instance every few hrs.   If I understand correctly, it sounds like you are saying its fixed with new recordings after a full v30 upgrade.  That would be good news.
>   > > > BTW, what is your recording source, HDHomeRun?
>   > >
>   > >Not on HDHomeRun, i'm using a TBS 6981 dual DVB-S2 card. FE is a 2820 celeron NUC.
>   > >forgot to mention that the playback data doesnt show anything obvious. full buffer, good codec (h264 vaapi) and jitter seems normal
>   >
>   > For digital recordings, the card used does not matter, as the
>   > recording process just copies to disk all the data streams that make
>   > up the channel.  The data in those streams is not touched at all.  So
>   > what matters is what the station is transmitting in those streams.
> seems i've got 2 issues with mine. one is a video scan setting where it's extremely jerky and unwatchable, and the other is as per my first mail where it'd periodically drop a frame. Haven't found any consistency with it yet other than it only /seems/ to occur on some HD recordings.  SD recordings and videos are unaffected.
> Found the first issues setting thats making it upset - video scan settings. Not sure what the default it, but forcing it to Progressive fixes things.
> I'm not seen the frame dropping issue recently.
> The Jerkiness issue seems to be a video scan issue as manually changing to Progressive or interlaced (reversed) setting is working on a recording from yesterday (so FE&BE on fixes/30) so definately not a pre-30 recording on a v30 FE. Using Detect or Interlaced (Normal) causes the jerkiness.
> I assume its not isolated just to my environment any ideas what to try?
> Annoyingly i did both Centos7 OS and Mythtv update at the same time; kernel, general packages (been many months since i last did an 'yum upgrade'), and compiled fixes/30 from git.

I don't know what capabilities your NUC has.  My SL7.6 + 
elrepo-4.4-kernel box, running Master, is currently playing an HD DVB-T2 
recording, getting it as a video from NAS.  Playback is mainly good but 
jerky on panning.  Video is old intel without hardware acceleration, 
Normal setting.  CPU is 2.8 GHz core2duo and display is VGA in a 
1024x576 window; 2 cores at 90% or above.

If I want to watch output from this box at full resolution I use DLNA.

Have you investigated the 'Advanced Playback Settings,' which were added 
quite recently with the aim, IIRC, of getting smoother playback and 
using VAAPI2?

John P

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